[PATCH V6 03/15] mmc: core: Add support for re-tuning before each request

Adrian Hunter
2015-04-20T12:12:17Z

At the start of each request, re-tune if needed and
then hold off re-tuning again until the request is done.

Note that though there is one function that starts
requests (mmc_start_request) there are two that wait for
the request to be done (mmc_wait_for_req_done and
mmc_wait_for_data_req_done). Also note that
mmc_wait_for_data_req_done can return even when the
request is not done (which allows the block driver
to prepare a newly arrived request while still
waiting for the previous request).

This patch ensures re-tuning is held for the duration
of a request. Subsequent patches will also hold
re-tuning at other times when it might cause a
conflict.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
drivers/mmc/core/core.c | 32 +++++++++++++++++++++++++-------
1 file changed, 25 insertions(+), 7 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index dd43f9b..a9936cb 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -186,12 +186,29 @@ void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)

EXPORT_SYMBOL(mmc_request_done);

+static void __mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
+{
+ int err;
+
+ /* Assumes host controller has been runtime resumed by mmc_claim_host */
+ err = mmc_retune(host);
+ if (err) {
+ mrq->cmd->error = err;
+ mmc_request_done(host, mrq);
+ return;
+ }
+
+ host->ops->request(host, mrq);
+}
+
static int mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
{
#ifdef CONFIG_MMC_DEBUG
unsigned int i, sz;
struct scatterlist *sg;
#endif
+ mmc_retune_hold(host);
+
if (mmc_card_removed(host->card))
return -ENOMEDIUM;

@@ -252,7 +269,7 @@ static int mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
}
mmc_host_clk_hold(host);
led_trigger_event(host->led, LED_FULL);
- host->ops->request(host, mrq);
+ __mmc_start_request(host, mrq);

return 0;
}
@@ -422,17 +439,16 @@ static int mmc_wait_for_data_req_done(struct mmc_host *host,
cmd->opcode, cmd->error);
cmd->retries--;
cmd->error = 0;
- host->ops->request(host, mrq);
+ __mmc_start_request(host, mrq);
continue; /* wait for done/new event again */
}
} else if (context_info->is_new_req) {
context_info->is_new_req = false;
- if (!next_req) {
- err = MMC_BLK_NEW_REQUEST;
- break; /* return err */
- }
+ if (!next_req)
+ return MMC_BLK_NEW_REQUEST;
}
}
+ mmc_retune_release(host);
return err;
}

@@ -471,8 +487,10 @@ static void mmc_wait_for_req_done(struct mmc_host *host,
mmc_hostname(host), cmd->opcode, cmd->error);
cmd->retries--;
cmd->error = 0;
- host->ops->request(host, mrq);
+ __mmc_start_request(host, mrq);
}
+
+ mmc_retune_release(host);
}

/**
--
1.9.1